Free action games came out with Battleship's vendetta, the coolest game of this genre. It is a ready to play game, without any complicated controls. The start of the game may put a smile to you face, which can be dangerous.
It does get more challenging as the time passes. You have to shoot alien spaceships down to collect money prizes and buy better, bigger, more powerful weapons for your own spaceship. It is a shot of adrenaline.
